Pse help me out of my misery
Discussion
My 69 Alfa Romeo 1300 Nord engine is making a rattling noise which has kept me and my local Indie guessing.
The engine starts on the button, pulls ok for a 1300, does not smoke on start or when warmed up, and neither does it smoke on the over run.
There is no rattle evident until the engine starts warming up (after say 5 minutes of running). The rattle appears to be from the top end but not from one specific cylinder (across all four it sounds). I've tried listening, screw driver to the ear etc. The rattle can be heard as the revs drop through 2200 rpm and disappears at 2000 rpm. The noise sounds more like a krrrrr noise than a deeper knocking noise - almost like a timing chain that needs tensioning.
The AR specialist thinks it could be piston slap, and suggested I replace all four pistons and liners. With the sketchy info above, does that sound probable?
Many thanks
The engine starts on the button, pulls ok for a 1300, does not smoke on start or when warmed up, and neither does it smoke on the over run.
There is no rattle evident until the engine starts warming up (after say 5 minutes of running). The rattle appears to be from the top end but not from one specific cylinder (across all four it sounds). I've tried listening, screw driver to the ear etc. The rattle can be heard as the revs drop through 2200 rpm and disappears at 2000 rpm. The noise sounds more like a krrrrr noise than a deeper knocking noise - almost like a timing chain that needs tensioning.
The AR specialist thinks it could be piston slap, and suggested I replace all four pistons and liners. With the sketchy info above, does that sound probable?
Many thanks
I had a similar dilemma to yourself recently, although not the same engine – a Lancia twincam block with 16v integrale head. It developed a ‘tappy’ type noise which I could of sworn was coming from the head, but an engine builder I know said that it could have run a main bearing. I stripped the oil filter and yes there were small metal particles, so I then stripped the engine and on removing the last (centre) main bearing cap, low and behold in had indeed run a bearing!
So I would check your filter and if you can drop the sump, check the bearings first. Fingers crossed it isn’t the problem but might be cheaper than 4 new pistons and liners.
Cheers,
Chris
So I would check your filter and if you can drop the sump, check the bearings first. Fingers crossed it isn’t the problem but might be cheaper than 4 new pistons and liners.
Cheers,
Chris
If there is no noise on the power run, but it appears when dropping power I would be tempted to check the timing chain/timing chain tensioner.
When accelerating, the tension is on, when decelerating the tension comes off so a loose chain would wallop around.
When cold, the oil is thick, when hot it isn't, so the chain would be less likely to "stick" due to the viscosity thinning out.
Same goes for hydraulic tappets. If they are worn, they will tend to move more when the oil is thinner.
When accelerating, the tension is on, when decelerating the tension comes off so a loose chain would wallop around.
When cold, the oil is thick, when hot it isn't, so the chain would be less likely to "stick" due to the viscosity thinning out.
Same goes for hydraulic tappets. If they are worn, they will tend to move more when the oil is thinner.
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